Low-pressure warning device



1954 R. R. CROOKSTON ETAL 2,697,999

LOW-PRESSURE WARNING DEVICE Filed April 22, 1953 2 sheets-sheet} I i 29F! G. I. 22 I !6- INV ENTOR.

Rqberf R. Crooksfon, By Irving Maser,

ATTOR E Dec. 28, 1954 R. R. CROOKSTON ETAL LOW-PRESSURE WARNING DEVICEFiled April 22, 1953 ii. l

2 Sheets-Sheet 2 F I G. 3.

11 72 Ill 62 mmvrm Robert R. Crooksfan, BY Irving Maser,

ATTO N United States Patent LOW-PRESSURE" WARNING' DEVICE RobertR..Crookston.and Irving Moser, Houston, Tex.,

assignors, by mesne assigmnenta tot Standard Oil D'evelopmentCompany,uElizabeth, N. J., a corporation of Delaware Application April22, 1953, ,SerialN=..350,496

3 Claims. (Cl...11634) I The-present invention isdirected'ato' a lowpressure warning device. rected to a device which-is operative. whenpressure falls below a predetermined figure. In its more specificaspects, the invention is directed to a low air-pressure warningdevice-which emits an audible .signal.

Moreparticularly, the invention is di- The present invention may. be briefly describ ed as a L Asecond-lateral passageway arranged in thechamber and is connected. to themovable valve actuating member and withthe housing. Spaced apart from the firstdiaphragm inthe chamber is asecond diaphragm whichis-provided with-ports communicating fluidly thefirst and second passageways. A

valve is arranged in the housing which-base valvestem 1 normally ininoperative relationship with the valve actuating member. A biasingmeans, such ,as-ahelical coil spring, embraces the valve actuatingmember and normally urges the valve actuatingmember toward and holds thevalve actuating member intoengagement with the valve stem. The housinghas an audible warning means connected thereto and to thechamber whichallows the warning means--to be actuated by the biasing means overcominga pressure exerted in a space between the diaphragms.

The valve may be arranged above: the-first-diaphragm and within thecentral'bore suchthat onthe-valve actuating member pressing against thevalve stem air is allowed to pass intothe audible' means andcausesasignal to be emitted. Preferably,- however, the valve is arranged in theinlet in relationship with thevalveactuating member such that on thebiasing means overcoming the diaphragms thevalve stem is urgeddownwa-rdly allowing air to pass from-the inlet through, the centralbore to theaudible means causing-asound' tobe emitted. a

The invention will be furtherillustrated by--reference to the drawing inwhich Fig. l is a sectional view of a preferred device;

Fig. 2 is a partial sectional viewof the valve employed in the presentinvention; andz i t Fig. 3 is a sectional view of another modificationof the invention.

Referring now to thedrawingand first to Fig. 1, numeral 11 designatesahousing having an inlet 12- which is designed to be connected byexternal threads 13 to a i source of pressure such as a tank and thelike. The inlet 11 has a orifice 14 and a recess 15 in which is arrangeda felt or cotton filter 16 to prevent passage of debris or dirt and thelike into the inlet 12. Connecting to the source of pressure is a firstlateral passageway 17 in the housing 11 which is parallel to the inlet12 and then turns obliquely and terminates in a recess 18. The housing11 is constructed in two parts which are designated as 19 and 20 andwhich is held together by a threaded bonnet 21.

The housing 11 encloses a chamber 22 in which is arranged diflerentialdiaphragms 23 and 24. The diaphragm 23 is held against the lower part 20by an annular plate 25 which also holds the diaphragm 24 against theupper part 19 of the housing 11.

The diaphragm 23 is providednwith. a port: or: ports 26 whichallows thepassageway 17 to communicate through. recess 18 with. a secondlateralspassageway. 27i Lateral .passageway 17' and. lateral passageway27 therefore communicate: with space 28 enclosed by the diaphragms 23.and. 24.

Arranged in the chamber 22.is a valve actuatingmem' ber 29 which isprovidedwith a central-bore 30 which runs the length thereof andcommunicates with the lower portion of chamber. 22. through a lateralbore 31.- The valve. actuatingmember. 29 defines an external shoulder 32which. providesta seat for'the diaphragm 24". The diaphragms 23. and 24are held against-=the -valve actu ating member 29' by' a :cylindrical.sleeve 33 which maintains a tight fit and holdsthewtwo diaphragms'snuglyagainst the member 29' with the aid of rubber cement and the like:adhesive...

Embracing .the .upper .end of the member -29--isa biasing means, such vas a helical coil spring 34,-one -'end of twhichbears .against the upperinteriorwall---3S--of housing 11 and the other endof whichbears-againstthe shoulderv 32. of the member 29.

Attached to an upper end of the housing -1 1-,is-'-an audiblewarningmeans 36 which maybe a suitable-whistle which communicates withthe chamber 22*through an orifice 37 through a lateralpassageway 38 anda longitudinal passageway 39.

Arranged in inlet'12..is a valve generally indicatedas 40 which isprovided. witha valve stem 41 -which 1 is adapted. to beurged downwardlyon engagement with valve actuating means 29.

The valve 40 is attached to the housing 11' in theinlet 12.. through.mating'. threads. 42 and is sealed therein throughsa deformable sealingmember 43.

InuFig. ;2 a detailed, partially sectional view oi the valve: 40 isgiven... It will be seen that-the valve 40 =is provided with valve stem41, a sealing member 43, and a threaded collar. 44 provided with threads'42. t The barrel 45' of the valve 4i) encloses a central .bore 46through which the .valve stem extends. The valve stemis biased upwardlyagainst a shoulder 41' defined by valve stem 41 bya helical coil spring47 which embraces the valve stem 41. The valve is held in the closedposition by the spring 47 to prevent passage of air around the seal 48and: seat 49.

A further embodiment of the invention is shown in Fig. 3 wherein.numeral 50- designates a valve housing comprised of an upper part 51 anda lower part 52; Arranged .on/the valvehousing 50 isa suitable whistle53 which :communicates fluidly with a chamber 54 enclosed lgythe housing50 by-wayof a longitudinal "passageway Thelower part 52 of the housing50-is provided with external threads 56 and is also provided-with aninlet 57 to allow air or other gas to be led into the-deviceunderpressure; Extendinglaterally from the inlet .57- are passageways 58which communicate, aswill-be described later, with second passageways59, the passageways 59 being bored in a third portion 60 of the housing50".- The upperhport-ion S1 is connected to the middle portion 60bymeans of threaded bolts 61- while the-middle portion is connected tothe lowerportion158j by threaded bolts Arranged in the chamber 54 is avalve actuatingmember generally designated as 63 which is comprised of alongitudinally extending portion 64 -on which is threadably arranged acap 65 having passageways 66. The cap 65 engages by mating threads 67with the extension 64. The valve actuating member generally indicated as63 defines a first shoulder 68 and a second shoulder 69 between which isarranged a diaphragm 70 which is held in the housing 50 between theupper portion 51 and the middle portion 60, as shown.

The extension 64 has an annular projection 71 on which is arranged asecond diaphragm 72 which is held in the housing 50 between the middlepart 60 and the lower part 52, as shown. The diaphragm 72 is providedwith a port or ports 73 which allow fluid communication betweenpassageway 58 and passageway 59 and thence to the space 74 between thediaphragms 70 and 72.

Within the central bore 75 of the valve actuating memberss is arranged alongitudinally extending member 76 which carries a valve such as 40which has been described with respect to Figs. 1 and 3. Since the valve40 in this embodiment of my invention is identical to the valve 40 ofFigs. 1 and 3, further description thereof need not be had. Suffice tosay that the valve 40 is threadably arranged in the member 76 by matingthreads 42. The member 76 is threadably connected by mating threads 77with the lower portion 52 of the housing 50. A passageway 78 running thelength of the member 76 communicates through orifice 79 with the inlet57. An inset member 80 is provided which engages threadably by threads81 with the member 76 and allows the orifice 79 to be varied at will. Asealing member, such as an O-ring 82, provides a seal and prevents fluidfrom escaping around the threads 77 and into the chamber 54 below thediaphragm 72. The clearance 83 between the member 76 and the member 64is vented through lateral ports 84 which communicate with chamber 54.

Surrounding and embracing the member 63 is a biasing means 84, one endof which bears against the shoulder 68 and the other end of which bearsagainst a shoulder 85 of a cylindrical sleeve 86 which rests on theshoulder 63. The member 63 is held snugly against the diaphragm 70 by anut 87 by mating threads 88.

The device of the present invention works in the following manner withrespect to Fig. l:

The device is assumed to be connected by threads 13 to a tank or conduitcontaining compressed air, gas or the like. It is desired that thewhistle 36 blow when the pressure in the tank to which the device isconnected falls below a predetermined level. The orifice 14 and the port30 and passageway 37 would be selected to give the de sired operationwith the differential diaphragms 23 and 24. Assuming that 90 poundssupply pressure enters through inlet 12 and passageways 17, the orifices30 and 37 would be selected so that the pressure below the diaphragm 23is 6 pounds per square inch gauge while the the pressure above thediaphragm 24 is 2.5 pounds per square inch gauge. The spring 34 would bedesigned to overcome the difierential pressure of the diaphragms 23 and24 with the orifices being adjusted as required. As suming that properadjustment has been made for the selected pressure, then the spring 34would overcome the diaphragms 23 and 24 when the pressure in inlet 12falls below a desired point. With the pressure being exerted in thespace 28 the assembly 29 would be held off of the valve stem 41preventing air from passing through the valve 40 into passageway 35 andthence by passageways 38 and 39 and orifice 37 into whistle 36. Thuswhen the pressure is held constant no signal will be emitted. On theother hand, if the supply pressure in passageway 17 should drop onlyslightly the spring 34 would overcome the differential diaphragms 23 and24 which would cause the member 29 to bear against the valve stem 41 andin turn would cause the valve stem 41 and seal 48 to move off of theseat 49 allowing air to pass through the aforesaid passageways and intothe whistle 36 causing an alarm. The passageway 17 must be upstream oforifice 14 so that passageway 17 always contains supply pressure. Whenthe whistle is blowing, orifice 14 causes a pressure drop in the inlet.Therefore, the pressure in the inlet will never reach supply pressure aslong as the whistle is blowing. However, with the above describedarrangement of passages, the pressure in passageway 17 will build up asthe supply pressure builds up to a point where the whistle will stopblowing even though the pressure in the inlet is low.

The device of Fig. 3 operates similarly to the device of Figs. 1 and 2.Assuming again that the device is connected by threads 56 to tanks orconduits under pressure the differential diaphragms 70 and 72 would beholding the cap off of the valve stem 41 preventing air or gas fromescaping into the passageway 55 and thence through whistle 53 to emit asignal. Thus the helical coil spring 84 tends normally to urge themember 63 downwardly causing the cap 65 to press against the stem 41unseating the valve. However, the differential diaphragms and 72 onhaving pressure exerted through passageways 58 and 59 against them inspace 74 serves to hold the spring and works thereagainst preventing thecontact of cap 65 with the stem 41. When this happens no signal isemitted. However, if the pressure in inlet 57 drops slightly then thespring 84 overcomes the difierential diaphragms 70 and 72 and the cap 65presses against the stem 41 allowing air to pass from inlet 57 throughorifices 79 into passageway 78 and thence through the valve 40, throughport 66 and passageway 59 into whistle 53 and to the atmosphere by wayof which a sound alarm is emitted.

The device of the present invention is useful where compressed air isemployed in oil drilling and other operations where the operators need awarning against low pressures. The device may be used in connection withair brakes, clutch shifting, clutch actuation and other requirementswhere and/ or gas pressure is employed. The device is advantageous inthat it employs only a small amount of air. For example, the size may beregulated to emit approximately 1 to 2 cubic feet of air per minute toblow the whistle. In fact, one of the advantages of our device is thatit uses only a small amount of air.

The nature and objects of the present invention having been completelydescribed and illustrated, what we wish to claim as new and useful andto secure by Letters Patent 1. A low pressure warning device adapted tobe connected to a source of pressure which comprises, in combination, ahousing enclosing a chamber provided with an inlet, a first lateralpassageway in said housing adapted to communicate with said source ofpressure, a second lateral passageway in said housing communicating saidchamber with said first lateral passageway, a movable valve actuatingmember provided with a central bore arranged in said chamber, a firstdiaphragm in said chamber, a second diaphragm spaced apart from saidfirst diaphragm in said chamber provided with ports communicatingfluidly said first and second passageways, said diaphragms beingoperatively connected to said valve actuating member, a valve arrangedin said housing in fluid communication with said inlet having a valvestem normally in inoperative relationship with said valve actuatingmember, biasing means embracing said valve actuating member normallyurging said valve actuating member toward and holding said valveactuating member into engagement with said valve stem, and an audiblewarning means arranged on said housing and fluidly connected to saidchamber adapted to be actuated by said biasing means overcoming pressureexerted through said passageways in the space between said diaphragms.

. 2. A device in accordance with claim 1 in which the valve is arrangedwithin the central bore.

3. A device in accordance with claim 1 in which the valve is arranged inthe inlet.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,417,168 Harris May 23, 1922 2,250,077 Henry July 22, 1941

